1. Field of the Invention
The present invention relates to a magnetic storage device that can store information therein by using a magnetoresistive effect.
2. Description of the Related Art
Conventionally, a magnetic storage device called as a magnetic random access memory (MRAM) that can store information therein by using a magnetoresistive effect is widely known as a nonvolatile memory device that can operate at high speeds.
The magnetic storage device is required to efficiently perform writing to a magnetoresistive element in order to achieve improvement of an operation speed, reduction of writing current, and the like. For example, a magnetic storage device is proposed that includes an approximately annular magnetic yoke for concentrating a magnetic flux generated around a wiring on a magnetoresistive element (see Japanese Patent Laid-Open Publications Nos. 2000-90658 and 2004-128430, for example).
However, it is necessary to increase the magnetic flux concentrated on the magnetoresistive element by making the magnetic yoke larger in order to further reduce the writing current in the conventional magnetic storage device. Thus, the reduction of the writing current in the magnetic storage device that has to be made compact has a limitation.